Method

You can either blend the butter and sugar together till pale, soft and creamy in a food processor or else use an electric hand whisk.

When you have a pale smooth mixture you can gradually add the rum, a little at a time, beating well after each addition. Taste and add more rum if you think it needs it! Then place the butter in a freezer box or bag and transfer to the freezer.

Brandy Butter variation: Use about 6 tablespoons of brandy instead of rum.